Gearbox zil 157 (Course project)

Contents

1 VEHICLE TRANSMISSION DEVICE ZIL-

2 DISASSEMBLY AND ASSEMBLY OF GEARBOX

3 SELECTION OF PARAMETERS OF STEPPED GEARS

TRANSMISSIONS

3.1 Initial data for calculation

3.2 Selection of gear parameters

3.3 Calculation of geometrical parameters of gearbox gears

4 CALCULATION OF GEAR WHEELS OF GEARBOX FOR STRENGTH

5 CALCULATION OF GEARS FOR FATIGUE STRENGTH

AND DURABILITY

6 CALCULATION OF GEARBOX PRIMARY SHAFT

6.1 Calculation of shaft for static strength

6.2 Calculation of shaft for stiffness

6.3 Calculation of splines of the primary shaft

7 SYNCHRONIZERS

8 SELECTION OF BEARINGS

LIST OF SOURCES USED

Transmission device zil-157

The gearbox allows, at the same number of revolutions of the engine crankshaft, to change the number of revolutions in the power transmission units of the car, and therefore, to change the force applied to the driving wheels of the car.

The gearbox of the ZIL157 car is three-way, five-speed with five gears for forward movement and one for backward movement. The fourth gear is direct, the fifth is increasing. Pairs of gears of third and fifth gears have oblique tooth and are in constant engagement. The gears are free to rotate on the secondary shaft. The first and second gears are engaged by the gears respectively. Reverse transmission is performed by switching on the gear block of reverse gears between the gears of the intermediate shaft and the gear block. Third, fourth and fifth gears are engaged by toothed clutches with internal engagement.

The gears are manually switched by means of a lever located on the gearbox cover. As the lever moves forward or backward, the sliders move. Together with the slider, one of the forks connected to the gears or clutch moves.

Disassembly and

assembly of gearbox

The gearbox can be removed from the car and put in place without removing the engine. When removing the box, it is only necessary to support the rear of the engine or the clutch housing from lowering with something .

Disassemble the box in the following order: at neutral position of gears, remove the side cover, gimbal flange, speedometer drive connector and rear cover; remove spacer bushings of speedometer gear from the secondary shaft and press the ball bearing; press the axle of the intermediate shaft gear unit towards the rear cover and lower the unit to the bottom of the crankcase; sleep the primary shaft cover and remove the primary shaft; remove the secondary shaft assembled with synchronizer and both gears through the crankcase side hatch.

Gearbox assembly must be done in reverse order.

For proper operation of the gearbox (noiselessness, lack of self-disconnections, duration), it is very important that it is precisely aligned with the engine. This is ensured by the rigidity of the clutch case and the precise treatment of its surfaces for the landing of the gearbox. Surfaces are machined together with engine unit, base for machining being crankshaft main bearings.

When the gearbox is installed in place, it will take the correct position if the clutch case has not been removed from the engine. The sealing surfaces of the crankcase of the box must be clean, without nicks and tightly drawn to each other.